Method and Apparatus for an Adaptive Threshold of a Zero Crossing Comparator Based on the Current in the Parasitic Bipolar Transistors
AssigneeDialog Semiconductor GmbH
InventorJindrich Svorc
Life of this patent
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Abstract
A buck converter device with a zero-cross comparator with an adaptive threshold. The buck converter comprises of a control block that controls a first p-channel MOSFET switch, and a second n-channel MOSFET switch. The p-channel MOSFET switch and the n-channel MOSFET switch provide a sense signal utilizing parasitic bipolar junction transistors. The p-channel MOSFET provides a sense current for the pnp parasitic bipolar junction transistor, The n-channel MOSFET provides a sense current for the npn parasitic bipolar junction transistor. The sense current is stored on a capacitor, and establishes an adaptive offset adjustment to a zero-cross comparator.
Claims27
A buck converter device comprising:
- a first switch device with a first parasitic bipolar junction transistor configured to provide a first sense signal;
- a second switch device with a second parasitic bipolar junction transistor configured to provide a second sense signal;
- and,
- a zero-cross comparator with an adaptive threshold configured with an offset adjustment provided from said first sense signal, and said second sense signal.
A voltage converter device comprising:
- a first switch device with a first parasitic bipolar junction transistor configured to provide a first sense signal;
- a second switch device with a second parasitic bipolar junction transistor configured to provide a second sense signal;
- a capacitor configured to provide charge storage for said first sense signal, and said second sense signal;
- a zero-cross comparator with an adaptive threshold whose first and second input are electrically connected to said second switch device
- a feedback loop electrically connected to said capacitor configured to provide an offset adjustment for said zero-cross comparator;
- and,
- a control block configured to provide electrical controls for said first switch device, and said second switch device configured to provide an input signal comprises of an adaptive threshold signal from said zero-cross comparator.
A method of adaptive threshold control for a zero-cross comparator comprising the steps:
- providing a buck converter comprising a first MOSFET switch with a first parasitic bipolar transistor, an second MOSFET switch with a second parasitic bipolar transistor, a sense capacitor element, a zero-cross comparator, an offset adjustment feedback loop, a control block, an inductor, and a output capacitor;
- sensing a signal from said first parasitic transistor;
- sensing a signal from said second parasitic transistor;
- storing a sense signal on said sense capacitor element;
- providing a sense signal to said offset adjustment feedback loop;
- adjusting the zero-cross comparator response from said sense signal;
- generating an output signal from said zero-cross comparator to said control block.
Dependencies are inferred from the claim text.